Alcohol damages day-to-day memory function

New research shows that heavy alcohol use also damages day-to-day memory, which includes prospective memory, remembering to do things at some future point in time, and everyday memory, remembering to complete daily activities.

This damage occurred within drinking limits suggested by U.K. government guidelines.

Research has shown that heavy alcohol use clearly damages retrospective memory, that is, the learning, retention and retrieval of previously presented materials. Less is known about the effects of alcohol on day-to-day memory function, specifically, prospective memory, remembering to do things at some future point in time, and everyday memory, remembering to complete daily activities. A study in the June issue of Alcoholism: Clinical & Experimental Research uses internet-based methodology to find that heavy alcohol consumption has a negative impact on day-to-day memory.

"Prospective memory impairments include things like forgetting to send someone a birthday card on time, or forgetting what you're going to say in the middle of a sentence," said Jonathan Ling, a senior lecturer in psychology at the University of Teesside in the United Kingdom and first author of the paper. "Everyday memory failures include telling someone a story that you've told them before, or forgetting where things are normally kept. Obviously we all forget things from time to time, however, heavy users of alcohol make noticeably more of these mistakes than either non- or low-users of alcohol." Ling added that most of what is known about heavy drinkers' retrospective memory function is based on laboratory research, and even less is known about alcohol's effects on normal memory-related tasks that people perform from day to day.

For this study, researchers collected data from 763 participants (465 female, 298 males) using a specially created website on the University of Westminster web server. Memory was assessed using two self-report questionnaires: the Prospective Memory Questionnaire (PMQ), and the Everyday Memory Questionnaire (EMQ). The PMQ has three sub-scales that measure short-term habitual PM, long-term episodic PM, and internally cued PM. Respondents also self-reported their level of use of alcohol and other drugs by responding to the UEL (University of East London) Recreational Drug Use Questionnaire.

The results indicate a dose-dependent effect of alcohol use on day-to-day memory function.

"We found that heavy users of alcohol reported making consistently more errors than those who said that they consumed little or no alcohol," said Ling. "A typical heavy user of alcohol reported over 30 percent more memory-related problems than someone who reportedly did not drink, and almost 25 percent more problems than those who stated they drank only small amounts of alcohol. More specifically, those participants who reported higher levels of alcohol consumption were more likely to miss appointments, forget birthdays and pay bills on time. Deficits in everyday memory included problems with remembering whether they had done something, like locking the door or switching off the lights or oven, or forgetting where they put items like house keys."

Colin R. Martin, a lecturer in mental health in the department of health sciences at the University of York, and honorary consultant psychologist to the Addiction Service and National Monitoring and Evaluation Center of the Salvation Army, said these results "contribute to the increasing evidence base that a diverse range of memory impairment is associated with excessive alcohol consumption. The underlying mechanisms responsible for memory deficits associated with excessive alcohol consumption are multi-factorial and, in many areas of specific deficit, continue to be currently poorly understood. This study is important because it extends our knowledge of alcohol-related memory impairment to everyday situations that most people can identify with, in contrast to laboratory-based memory tasks."

"We also found a significant increase in reported memory problems by people who claimed to drink between 10 and 25 units each week in comparison to non-drinkers," added Ling. One unit of alcohol is the equivalent of 10 ml of ethanol; roughly half a pint of beer or one small glass of wine. Current U.K. guidelines for maximum safe units per week are 21 units for women and 28 units for men. "This is an important finding, as it indicates that even if people are using alcohol within the limits suggested by U.K. government guidelines, these individuals still report experiencing memory problems."

Martin concurred. "Interested readers may wish to reflect on the relevance of government recommended 'safe' drinking limits, since decreased memory performance was observed even within what is generally acknowledged as 'safe' drinking levels," he said. "Recommended levels may be 'safe' for the liver, but we can't be sure that they represent 'safe' limits for optimum brain function."

Martin suggested that the role of deficits in day-to-day memory performance should be explored and extended to those individuals receiving treatment for alcohol-dependency problems. "Memory deficits are common in individuals who are receiving in-patient and community treatment for alcohol dependency," he noted, "yet assessment of everyday memory performance in this group has yet to be established. This is particularly important because a number of the counseling and relapse prevention therapies and strategies used in this group are reliant on a fundamentally intact memory system."

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Alcoholism: Clinical & Experimental Research (ACER) is the official journal of the Research Society on Alcoholism and the International Society for Biomedical Research on Alcoholism. Co-authors of the ACER paper included: Tom M. Heffernan and Andrew B. Scholey of the Human Cognitive Neuroscience Unit in the Department of Psychology at the University of Northumbria; Tom Buchanan of the Department of Psychology at the University of Westminster; Jacqui Rodgers of the Department of Clinical Psychology at the University of Newcastle; and Andy C. Parrott of the Recreational Drugs Research Group in the School of Psychology at the University of East London.

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